Pneumatically operated sawmill dog



Jan. 27, 1953 w. F. CAHOON PNEUMATICALLY OPERATED SAWMILL DOG 7 Sheets-Sheet 1 Filed Aug. 8. 1949 W. F. CAHOON PNEUMATICALLY OPERATED SAWMILL DOG Jan. 27, 1953 '7 Sheets-Sheet 2 Filed Aug. 8. 1949 INVENTOR.

mum/n 5 CHHOON HTTWNAEYJ '7 Sheets-Sheet 5 IN VEN TOR.

I flrromvsYs W. F. CAHOON PNEUMATICALLY OPERATED SAWMILL DOG Jan. 27, 1953 Filed Aug. 8, 1949 WILL/HM F- CHI- DON Jan. 27, 1953 w. F. CAHOON PNEUMATICALLY OPERATED SAWMILL DOG 7 Sheets-Sheet 6 Filed Aug. 8, 1949 f7 TTORNEYS W. F. CAHOON PNEUMATICALLY OPERATED SAWMILL DOG Jan. 27, 1953 7 Sheets-Sheet '7 Filed Aug. 8. 1949 INVENTOR. WILL/HM F CHHOON Patented Jan. 27, 1953 NI ED STATES P PNEUMATICALLY OPERATED SAWMILL DOG William F. Cahoon, Birmingham, Ala., assignor, by decree of distribution, to Una Thomas Cahoon Application August 8; 1949, Serial No. 109,131

- Claims.

This invention relates to that type of log and lumber dogging apparatus which is operative by fluid pressure and has for one of its objects the provision of apparatus of the character designated, which shall be so constructed that the weight'of all the dogging mechanism, except the guide for the dogvb'ar cases and its supporting members is transferred to the center of the head block and in .which'lthe dog cases, dogs, and dog movement cylinders are disposed on the outside of'the knee; affording accessibility and ease of maintenance.

inventioncontemplates apparatus in which the upper dog case, with its dogs, is raised to dogging position by an upward thrust of the piston of an air operated cylinder, with the piston rod attached to a cross head and to the upper dog case. When dogging pressure is exerted on the top of the piston, bringing the upper dog down upon the timber and at rest, the pressure continues on the upper cylinder head causing it to raise, bringing with it the lower dog case, which is attached to the cylinder by a suitable connection. The cylinder in its upward movement is guided by guide rods which are secured to 'the supporting base of the cylinder and which fit slidingly into sleeves operatively connected to the cylinder.

A further object of my invention is to' provide pneumatically operated apparatus for log and lumber dogs in which the air cylinders are mounted between the two sides of the knee, with the cylinders movably supportedon" a suitable base between the knees, and with improved guidingLmechanism which prevents contact of the cylinders with thesidewalls of v the knee and transfers vthe weight to the center of the head block.

Still' another object of my invention is to provide pneumatically operatedapp'aratus for operating the dogs in a sawmill whiohshall include an improved cylinder construction together with improved means for admitting air pressure to the undersideof the pistoninthe .cylinder.

.jAYstillfurther object of my invention is to provide', pneuma'tically operated apparatus for-the dogs in a sawmill which shall include a lower 'dog case, with improved means for supporting and actuating'it, whereby it is prevented from cocking. or binding on the dog case guide bar, together with means for adjusting the height of the lower dog case to compensate for wear and compression of the cylinder cushions Which- I employ.

A still further object of my invention is to provide dogging apparatus together with improved means for mounting and moving the. dogs inwag-(11y andputwardly of 'the dog' case, together withjmproved means for compensating for wear .btween the dog caseand the dog case guide bar.

Still another feature of my invention is the 2 provision of an improved means for warning the operator whenever the lower dog approaches an unsafe limit of travel forwardly of the dog case.

Apparatus embodying features of my invention is illustrated in the accompanying drawings, forming a part of this application, in which:

Fig. 1 is a side elevation showing the forward portion of the knee with the dogging apparatus;

Fig. 2 is a sectional side elevation, taken from the opposite side from that shown in Fig. l, with one side of the knee removedy Fig. 3 is a plan view of the apparatus;

Fig. 4 is a sectional view taken along the line IVIV of Fig. 1;

Fig. 5 is a detail view of'the upper dog with the sideplate of the dog case removed;

Fig. 6 is a front elevational view with parts broken away and in section; i

Fig. 7 is a rear elevational view with parts broken away and in section;

Fig. 8 is an enlarged detail sectional view of the dog operating cylinders;

Fig. 9 is a sectional view taken along the line IX-IX of Fig. 1;

Fig. 10 is a detail enlarged sectional view of an air cylinder for operatingone of the dogs;

Fig. 11 is an enlarged detail perspective view showing the dog case guide bar and its adjustable gibs; and r Fig. 12 is a side elevational view showing the rear portion of the knee and the safety operating mechanism for the lower dog.

Referring now to the drawings for a better understanding'of my invention, I, show a fragment ill of a head blockon which is mounted a hollow knee l l, the knee being movable on the head. block, forwardly and rearwardly, ina manner well understood and which needs no description.

The knee consists of two side plates l2 and i3 which are joined together at the front by a face plate l4 and at the rear by a cross member I6.

A cylinder support or base plate I! extends across between the side plates [2 and l3,.and is joined to both of said plates by welding or otherwise.

Attached to the side plate. l3 of the knee is a bracket l8 havin an upper arm l9 and a lower arm 2!, to which is secured a dog case guide bar 22 which extends from the top to bottom of the knee, 1

Mounted on, and vertically movable with'respect to the guide bar, is an upper dog "case 23. The dog case is comprised of twoinner side plates 24 and 26 which are'spacedapart to straddle the arms 19 and 2|, and permit verticalmovement of the case. The plates 24 and 26 are joined together at the topby a n operating bracket 21., The outer side of the upper dog case isjcomprised of twoflat spaced bars 28 and 29 and the front and rear by flatbars 3| and 32. The front and rear bars 3I and 32 are joined to the inner bars 24 and 26 by welding and the inner and outer bars are joined together by a suitable number of bolts 33, 34, 36 and 31 which support dog bar guides 38 and 39. They are also joined together by bolts II, 42, 43, and 44, which support the intermediate dog bar guides 48 and 41. As shown in Fig. 4 of the drawing, the dog bar guides are positioned outside, or beyond, the dog case guide bar 22 and thereby do not interfere with the vertical movement of the dog case on the guide bar 22. Mounted within the dog case 23 between the end members 3| and 32, and bearing against the dog case guide bar 22, are gibs 48 and 49. Similar gibs 53 and 54 are mounted alongside the intermediate dog bar guides 46 and 41. Each of the gibs is provided on its outer side with a pin 59 which fits within a suitable recess in the dog case to hold it in position. The gibs 49 may be adjusted inwardly of the dog case by means of set screws SI and 52, and the gib 54 may be similarly adjusted by means of set screws 56 and 51. By the means shown, the wear of the guide bar 22 and the gibs may be compensated. Vertical movement of the dog case 23 on the dog case guide bar 22 is limited by means of a stop block 35 which is disposed to engage a pin 49 On the guide bar at the upper limit of travel of the dog case.

Mounted between the dog bar guides 38 and 39 is an upper dog 59 and mounted between the intermediate dog bar guides 46 and 41 is an intermediate dog 6|. Each of the dogs 59 and 6| is provided with a downturned dogging point 62. Joined to each of the dogs 59 and 6| is a rearwardly extending rod63. A spring 64 surrounds the rod 63 and the rod extends rearwardly through a cross head 66 and is slidable with respect thereto. The cross head 66 bears against the spring 64 and nuts 61 on the outer end of the rod provide means to adjust the innermost position of thedog. As shown in Fig. of the drawing, the dog bar guides are mounted in the dog case by means of bolts passing through slotted holes 68 and 69 thereby providing means for compensating for wear of the dogs and the guides.

The upper dog 59 and the intermediate dog 6I are moved inwardly and outwardly by means of air cylinders TI and I2 which are similar in construction and operation and only one need be described. Mounted within the cylinder II is a piston I3 to which is connected a piston rod .14 having the cross head 66 mounted on the outer end thereof. Air is admitted to opposite sides of the piston I3 through. conduits TI and I8 in a manner well understood to cause the pistonto move'inwardly or outwardly. It will be seen that, with the construction described, in event a log or other piece of timber comes against the outer end of either of the dogs 59 or 6I, it will be pushed inwardly, compressing the spring 64 against the cross head 66 and thereby preventing damage to the dog. It will also be seen that whatever the position of the dogs, except when pushed inwardly by timber, the tension on the springs surrounding the dog rods is the same.

The dog case 23 is raised and lowered on the dog case guide bar 22 by means of two air cylinders I9 and 8Iwhich are movably mounted in the knee II between the side walls thereof on the base plate IT. A rubber cushion 82 is interposed between the lower ends of the cylinders and the base plate IT to cushion movements of the cylinder with respect to the knee. Formed 4 on the base plate H are threaded bosses 83 and 84 having vertically extending rods 86 and 81 secured therein. The rods 86 and 81 fit slidingly within sleeves 88 and 89 which are secured, at their upper ends, by means of studs 94 and 95 and nuts 85 and 99 to outwardly extending portions 9| and 92 of an upper cylinder head 93 which serves for both cylinders I9 and 8|. The sleeves 98 and 89 are secured at their lower ends to the common lower head 96 of the two cylinders I9 and BI and they thus hold the heads against separation. The upper and lower heads are also joined together by means of an air supply tube 91 which is screwed into the lower head and is threaded exteriorly and clamped downwardly with respect to the upper head. by means of nuts 98 and 99. The lower cylinder head 96 is formed with a passage I9I therein which leads to the lower ends of both the cylinders and connects with the air tube 91. Mounted within the cylinders I9 and BI are pistons I92 and I93 with piston rods I94 and I96 connected thereto. The upper ends of the piston rods are connected to the bracket 2'! by means of adjusting nuts I99 and I95. As before set forth, the bracket 21 is joined to the upper end of the dog case 23 and its position at rest with respect to the cylinders may thereby be adjusted. Air is supplied to the upper ends of the cylinders I9 and 8| by means of air conduits I97 and I98.

It will be seen that the mechanism just described provides a means whereby when air is admitted beneath the pistons I92 and I93, they move upwardly within the cylinders I9 and 8| to raise the dog case 23 and the dogs 59 and 6|. When air is admitted to the upper ends of the cylinders above the pistons I92 and I93, the dog case 23 and dogs 59 and GI are moved downwardly until they engage with a log or timber and are stopped thereby. Thereupon, the air acting against the upper heads of the cylinders raises the cylinders relative to the piston rods I94 and I96, the rods 86 and 81 acting as guides for the cylinders in their upward movement. This brings about upward movement of a lower dog now to be described.

Mounted on, and movable vertically with respect to the dog case guide bar 22, is a lower dog case I99. The lower dog case is comprised of two spaced parallel steel plates I I I and I I2 on the inner side, which are connected to bars H3 and I I4 by means of studs I I6 and I I1, and which bars extend upwardly and are joined at their upper ends to an extension II 8 on the upper cylinder head 93. The bars H3 and H4 are cylindrical at their upper ends and are threaded as shown to be joined to the extension I I8 by means of adjusting nuts H9 and I29 whereby the initial position of the lower dog case with respect to the knee can be varied; As shown in Fig. 9 of the drawing, the bars III and H2 overlap the dog case guide bar 22. Joined to the bars I I I and H2 and bearing against the sides of the guide bar 22 are guide blocks, or gibs I2I and I22. Joined to the guide blocks I2I and I 22 is an inner guide plate I23. Outer plates I24 and I26 are joined to the plate I23 by a lower spacer block I27, upper dog bar guide I28, and an intermediate dog bar guide I29.

Mounted in the lower dog case just described is a lower dog I3I, which, as shown in Fig. 1 is Z shaped in side elevation so that it bears on the lower spacer block I21 and lies between the intermediate guide I 29 and upper guide I28. Secured to the rear end of the dog I3I is a rod I32 having a spring I33 surrounding it in the same manner as the dogs already. described. Theouter end of the rod l 32 is threaded and passes through a cross head I34 having a slidable'fit with respect thereto. Adjusting nuts I36 and I31 are screwed onto the outer ends of the rod I32 to adjust the initial position of the dog. Also secured to the rear end of the dog I3I is a rod I38 forming a part of a safety device to, be described in detail hereinafter.

The lower dog I3I is moved inwardly and outwardly of the dog case I09 into dogging position by means of an air cylinder I39 which is mounted on the lower dog case. .The cylinder I39 is secured to the dog case by means of studs I4I, I42,

I43 and I44 which passes from end to end of the cylinder through heads I46 and I41 and into the dog case, on the outside of the cylinders, and secure the heads I46 and I41 against separation. Mounted in the cylinder I39 is a piston II having a piston rod I52. Secured to the outer ends of the piston rod is a plate, or cross head I34 which is slidably connected to the dog rod I32 and bears against the spring I33. Air is admitted to opposite ends of the cylinder I39, as "required, bymeans of air'conduits I53 and I54 in a manner well understood. The conduits I53 and I54, as shown, are relatively long and flexible whereby upon separation of the upper and lower dog cases, the air connections are not broken.

Referring now to Fig. 12, together with Fig. 1, I show in detail the construction and operation of the lower dog safety limit device. The rod I38 is connected to a movable cross head I56 which has connected thereto and extending forwardly therefrom a rectangular bar I51. The bar I51 fits slidingly within a guide I59 secured to the side of the knee II at the rear thereof. At I60 is indieated a tapering mechanism mounted on the knee II, which forms no part of my present invention. Accordingly it is not described in detail. Extending outwardly from the cross head I56 is a bracket ISI which moves forwardly and rearwardly with the cross head. Mounted on the head block is a valve case I62 having a plunger I63 extending rearwardly therefrom in the path of movement of the bracket I6 I. A set screw I64 extends through the bracket I6I to engage the stem I63. Air is admitted to the housing I62 by means of a conduit I66 and, upon opening of the valve by means of the valve stem I63 escapes through a conduit I61. When this occurs,: a

whistle I68, connected to the'conduit I61 is blown other well known forms of warning signal may be employed.

From the foregoing description, the operation of my improved dogging apparatus willv be read.- ily understood. With a piece oftimber .placed against the face plate I4 of the knee between the lower dog I3I and one of the dogs 59 or 6|, as the case may be, depending upon the thickness of the timber, the dogs are moved forwardly, if necessary, to dogging position whereby theycan engage the timber; With the dogs in position to engage the timber, air'is admitted to the upper ends of the cylinders 19"arid 0I through the'eon} duits I01and IUS'toforce'th e pistons downwardly carrying'with them the bracket 21 and dog'case 23 to lower the dogs 59 *and' '6I. As soon as the dog 59 or 6I, as the case may be, engages the timber, its further downward movement is arrested'and'the 'actionof the'air to the upper ends of the cylinders 19 and 0 I, raises the cylinders ofi their support carrying with them the extensions I I3, the lower dog case lift bars H3 and H4 and the lower dog case I09, thereby to raise the lower dog I'3I to'engage the lower side of the timber. When it is desired to release the timber, or move the dogs to another position, air is admitted to the lower ends of the cylinders 19 and 8| beneath the pistons I02 and I03 whereupon the pistons move upwardly; taking the bracket 21 and dog case 23, and. disengaging the upper dogs from the timber. At the same time, the cylinders 19 and BI are lowered by raising the pressure against the lower cylinder head, to lower the lower dog case I09 and-release the lower dog I 3| from the timber. While I have shownthe dog cases 23 and I09 asbeing raised and lowered by means of two air cylinder-s19 and BI, this is for convenience only and it will'b'e obviousthat more, or fewer, cylinders may be employed;

Fromthefforegoing, it will be'seen that with the cylinders 19 'and'8l located between the side walls of the knee, and the dog cases and dogs supportedfrom the cylinders, that all the weight of the apparatus is transferred to the head'block centrally of'the knee. Theonly weight carried by the-knee and laterally thereof is the weight of the dog case guide bar 22. The positioning of the upper and lower dog cases outside the knee renders them readily accessible for adjustment'and maintenance which is a veryimportant item in the operation of a sawmill. It will thus be seen that I have provided improved dogging apparatus which is simple and sturdy of construction, and which is readily adjusted and maintained.

While I have shown my invention in but one form, it will be obvious tothose skilled in the art that it is not so limited, but is susceptible of various changes and modifications, without departing from the spirit thereof, and I desire, therefore, that only such. limitations shall be placed thereupon as are specifically set forth in the appended claims. 7

What is claimed is:

1. In timber dogging apparatus including a knee having spaced side walls, a pneumatic cylinder having upper and lower heads and disposed between the sides of the knee, a support for the cylinder between the sides, a vertically disposed dog case guide bar supported by and extending alongside outwardly of the knee, a dog case mounted to move on the guide bar, a piston in the cylinder, a connectionbetween the piston and the dog case, a lower dog case mounted on the'lower end of the guide bar to move thereon, a connection between the cylinder and the lower dog case, guide means for the cylinder between the walls of the knees comprising guide rods secured to and extending upwardly from the cylinder support and sleeves slidingly fitting over said rods and secured to said upper and lower heads, and upper and lower dogs extending outwardly respectively from the upper dog case and the lower dog case.

2. In timber dogging apparatus including a knee having spaced side walls, a vertically diswallsof the knee, apiston in said cylinder,-a 'sup1- port-for .the cylinder spanning the spacebetween the side walls and joined thereto, a resilient cushion between the lower end of the cylinder and the support, guide rods secured to and extending upwardly from the cylinder support, upper and lower heads for the cylinder, outwardly extending portions on each of said heads, sleeves slidingly fitting over the guide rods and connecting the outwardly extending portions of said upper head to the outwardly extending portions of said lower head, an upper dog case supported from and movable with the piston, and a lower dog case supported by and movable with the cylinder.

3. Apparatus as set forth in claim 2 in which the sleeves are secured to said upper and lower cylinder heads and serve to retain the cylinder heads in place.

4. In timber dogging apparatus including a knee having spaced side walls, a cylinder support extending between the side walls, spaced rods secured to the support and extending upwardly therefrom, a pneumatic cylinder mounted on the support and having opposed heads connected by means including tubes which fit slidingly over the rods, a resilient cushion between the cylinder and the cylinder support, a piston in the cylinder, means to admit air under pressure selectively to opposite ends of the cylinder, an upper and a lower dog case mounted alongside the knee, means for supporting the upper dog case from the piston, means for supporting the lower dog case from the cylinder, and upper and lower dogs respectively mounted in the upper and lower dog cases and extending forwardly therefrom.

5. In timber dogging apparatus including a knee having spaced sidewalls, a vertically disposed dog case guide bar supported from the knee and positioned outwardly of the knee in spaced relation thereto, a dog case mounted on the guide bar and movable vertically with respect thereto,

a pneumatic cylinder having a piston therein said guide bar and extending outwardly there- 1 from, movable gibs mounted in the dog case and bearing against the sides of the guide bar, there being an opening in each gib of a size to receive one of said pins, and set screws bearing against the gibs to compensate for wear between the gibs and the guide bar.

6. In timber dogging apparatus including a knee having spaced side walls, a cylinder support extending between the side walls, spaced rods secured in the support and extending upwardly therefrom, a pair of pneumatic cylinders mounted on the support and having opposed common heads connected by means including tubes which fit slidingly over the rods, a resilient cushion between the cylinders and the cylinder support, pistons in the cylinders, means to admit air under pressure selectively to opposite ends of the cylinders, an upper and a lower dog case mounted alongside the knee, means for supporting the upper dog case from the pistons, means for supporting the lower dog case from the cylinders, and upper and lower dogs respectively mouted in the upper and lower dog cases and extending forwardly therefrom.

7. In timber dogging apparatus including a knee having spaced side walls, a cylinder support extending between the side walls, spaced rods secured in the support and extending upwardly therefrom, a pair of pneumatic cylinders mounted on the support and having opposed common heads connected by means including tubes which fit slidinglyover the rods, a resilient cushion between the cylinders and the cylinder support, pistons in the cylinders, means to admit air under pressure selectively to opposite ends of the cylinders, an upper and a lower dog case mounted alongside the knee, guide means for both dog cases carried by the knee, a bracket mounted on the upper ends of the pistons and extending outwardly of the knee where it is connected to the upper dog case, an extension on the heads of the cylinders and extending outwardly from the knee and from which the lower dog case is supported, and upper and lower dogs respectively carried by the upper and lower dog cases and extending forwardly therefrom.

8. In timber dogging apparatus, a hollow knee, a pair of pneumatic cylinders mounted in the knee, common upper and lower heads for the cylinders, the lower head having an air passage therein leading to both cylinders, an air supply tube extending through the upper head between the cylinders and connected to the lower head to supply air to said passage, threads on the upper end of the tube, and nuts on the threaded end engaging the upper cylinder head to hold the heads in place.

9. In timber dogging apparatus, a hollow knee, a pair or pneumatic cylinders mounted in the knee, common upper and lower heads for the cylinders, the lower head having an air passage therein leading to both cylinders, an air supply tube extending through the upper head between the cylinders and connected to the lower head to supply air to said passage, threads on the upper end of the tube, nuts on the threaded end engaging the upper cylinder head to hold the heads in place, a plurality of sleeves connecting the upper and lower heads and extending'through the .lower head, a support for the cylinders in the knee, and guide rods extending upwardly from the support into the sleeves.

10. In timber dogging apparatus, a hollow knee, a pair of pneumatic cylinders mounted in the knee, common upper and lower heads for the cylinders, the lower head having an air passage therein leading to both cylinders, an air supply tube extending through the upper head between the cylinders and connected to the lower head to supply air to said passage, threads on the upper end of the tube, and nuts on the threaded end engaging the upper cylinder head to hold the heads in place, a plurality of sleeves connecting the upper and lower heads and extending through the lower head, a support for the cylinders in the knee, guide rods extending upwardly from the support into the sleeves, and resilient cushioning means surrounding the guide rods and interposed between the cylinders and the support.

WILLIAM F. CAHOON.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS 

